I can not seem to find good answers for these questions on the internet or books from the library. I cannot find any references to the subject that is supported by actual scientific research or even scientific knowledge.

My specific questions are about the molecules in essential oils,

Are essential oil molecules small enough by molecular weight or mass to pass through the skin and enter the bloodstream? I have read that most essential oils molecular weight or mass is less that 500 daltons?

One article I read said that 500 daltons was the number for a molecule to pass through the lipid matrix of the dead cells on the surface of the skin. Another says 700 daltons. To me this is a big difference since most essential oils have a molecular mass of 500 and some carrier oils used like coconut and jojoba oils are between 500 and 700. Are either really absorbed into the layers of the skin and ultimately picked up into the bloodstream?

And even if the are absorbed do they pass into the blood stream through the capillary ends in dermis layer (is that where they are?)?

What happens when you mix essential oils with heavier molecular weight molecules in cold pressed vegetable and nut oils?

Do they adhere to the fat molecules and then become to heavy to be absorbed by the skin and thus never enter the blood stream?

Do essential oils molecules seek out and attach themselves to fat molecules? Then they would be stuck in that lipid layer of dead cells in the skin with all the fat content. Is that even a correct assumption?

There is so much conflicting information in aromatherapy that seems to never be backed up by simple biology and chemistry of the body. It is widely taught in aromatherapy classes and books that the pores on the feet are larger than any other part of your body and that when you put essential oils on the soles of your feet you are able to get to the bloodstream the fastest (second only to inhalation). I just don't see the Biological or Chemical proof for this theory. It is often stated as fact. I only see from basic anatomy that the sole of the foot has five layers of skin no hair and the largest amount of sweat pores so yeah if you want the essential oils in your sweat glands? I just can't find any medical or biochemistry knowledge to support this theory.I hope someone who has a better knowledge of the skin absorption and molecules can help me understand if these aromatherapy claims are true or not. Medicine is delivered in skin patches so seems if the molecules are small enough in essential oils it would work but I have never heard of putting a nicotine patch on the sole of your foot for quick absorption!

Hydrophobic substance does get through skin, that how a lot of medications work, Eg, Nicotine, and Nitroglycerin for heart attacks, Similarity a lot of toxins work the same way (seen them in action thrillers) , Does that help?

I've been trying to research the exact same thing. I am getting very curious about a number of emerging medical trials involving essential oils for things like cancer treatment, as well as their antimicrobial properties, etc. And I've found a surprising amount of actual, scientific evidence that essential oils are effective in treating a variety of maladies, not just through aromatherapy applications, but also when ingested or applied directly to the skin. But yeah, I can't find anything that talks about absorption through the soles of the feet that has any scientific backing. I found this discussion:http://ceaccp.oxfordjournals.org/content/7/5/171.fullwhich discusses skin patches as a way to dispense medicine. And it talks about the sweat glands being a one of the main structures medicine would use to pass through the epidermis. So maybe this is why the feet might be a good area for the application of essential oils? Maybe through trial and error it just so happens that essential oils prefer sweat glands as a path into the body? I'd love to see this backed by research.